Spark Plug
Thread Starter
Instructor
Joined: Nov 2009
Posts: 141
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From: Huntsville Alabama
Spark Plug
My '07 Z06 has about 52k miles and I've been working on the tune for the past couple of weeks. It occurred to me that I should check the spark plugs as I have no idea what the previous owners may have done. Anyway, I pulled one and it looks pretty fouled, but that doesn't surprise me as I had just spent about 30 minutes at idle doing some logging earlier in the afternoon. I know the iridium plugs are supposed to be good for 100k miles but do you think I should replace them? I also noticed the plug wires are made by MSD. I don't think I'm having any particular issue with them but I've read some folks had problems and went back to the stock wires. Below is a picture of the plug, although it's hard to get a good photograph.
Drifting
Joined: Apr 2006
Posts: 1,276
Likes: 5
From: Ambler Pa.
My '07 Z06 has about 52k miles and I've been working on the tune for the past couple of weeks. It occurred to me that I should check the spark plugs as I have no idea what the previous owners may have done. Anyway, I pulled one and it looks pretty fouled, but that doesn't surprise me as I had just spent about 30 minutes at idle doing some logging earlier in the afternoon. I know the iridium plugs are supposed to be good for 100k miles but do you think I should replace them? I also noticed the plug wires are made by MSD. I don't think I'm having any particular issue with them but I've read some folks had problems and went back to the stock wires. Below is a picture of the plug, although it's hard to get a good photograph.
Thread Starter
Instructor
Joined: Nov 2009
Posts: 141
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From: Huntsville Alabama
I just replaced the plugs and for what it's worth they all looked a bit better than what I saw in the original picture. They were still black around the base but the tip was a lighter tan color. Of course, they have been run normally for a few days since the original picture. I do think the car was running rich at WOT before I started retuning.
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Intermediate
Joined: Jul 2010
Posts: 46
Likes: 0
From: Summerville SC
While you're at it, you may as well "index your spark plugs" and "side gap" them a bit as well... you should notice a difference... I've seen 6 hp increases just from these small "racer tweaks".
Team Owner
Joined: Feb 2001
Posts: 27,236
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From: Short Hills, NJ
I wouldn't run any spark plug more than 30k miles (Iridium or otherwise), nevermind a full 100k.
In a stock/near stock and most NA applications, I would only use the OEM stock GM/AC Delco plugs wires...or new replacements of the very same if the originals are getting older/higher miles.
Former Vendor
Joined: Apr 2006
Posts: 2,470
Likes: 2
From: Portland OR
St. Jude Donor '10-'11-'12
My '07 Z06 has about 52k miles and I've been working on the tune for the past couple of weeks. It occurred to me that I should check the spark plugs as I have no idea what the previous owners may have done. Anyway, I pulled one and it looks pretty fouled, but that doesn't surprise me as I had just spent about 30 minutes at idle doing some logging earlier in the afternoon. I know the iridium plugs are supposed to be good for 100k miles but do you think I should replace them? I also noticed the plug wires are made by MSD. I don't think I'm having any particular issue with them but I've read some folks had problems and went back to the stock wires. Below is a picture of the plug, although it's hard to get a good photograph.
You can run either or plug in there... the copper based don't last as long so it comes down to maintenance interval and what you want.
The iridiums last longer...
Safety Car
Joined: Jan 2006
Posts: 4,598
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From: Miami FL
2020 C6 of the Year Finalist - Unmodified
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16,'17,'18-'19-'20-'21-'22
I'll repeat the question 'cause I would like to know, also:
" What is 'side-gapping' " ?
" What is 'side-gapping' " ?
SUBVETTE
Joined: Jul 2006
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From: San Diego CA
Le Mans Master
Joined: Dec 2009
Posts: 5,709
Likes: 6
From: Midwest
I checked the iridium plugs in my 01 ws6 at about 75k miles. Gap was dead on oem spec. Car got 27.5 mpg doing 75-80 and was epa rated at 28. left them in and never changed them. At 150k miles it still ran great, got 21mpg city and highway, and was a dead even race for every new camaro ss I ran. At 100k miles I bogged and granny shifted it to a 14.0@102 with a 2.35 60'.
I'm a fan of GM oem plugs.
I'm a fan of GM oem plugs.
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
My '07 Z06 has about 52k miles and I've been working on the tune for the past couple of weeks. It occurred to me that I should check the spark plugs as I have no idea what the previous owners may have done. Anyway, I pulled one and it looks pretty fouled, but that doesn't surprise me as I had just spent about 30 minutes at idle doing some logging earlier in the afternoon. I know the iridium plugs are supposed to be good for 100k miles but do you think I should replace them? I also noticed the plug wires are made by MSD. I don't think I'm having any particular issue with them but I've read some folks had problems and went back to the stock wires. Below is a picture of the plug, although it's hard to get a good photograph.
Safety Car
Joined: Jan 2004
Posts: 4,974
Likes: 14
From: Pinellas Park Fl
St. Jude Donor '08-'09 & '12, '14
Side gapping and indexing our sparking pins, what is this, the 70's?
Nothing more than crutches for poor chamber/bowl designs.
Side gapping is nothing more than trimming back the ground strap so that it aligns with the electrode. The thought was that it provided an unobstructed path for the flame kernel. Champion actually marketed plugs designed like this back when.
There is very little if any gains to be made doing either of these with todays head designs.
And your plug is fouled from being too rich, based on the picture, ie. flat dry black, I don't see shiny wet black.
Nothing more than crutches for poor chamber/bowl designs.
Side gapping is nothing more than trimming back the ground strap so that it aligns with the electrode. The thought was that it provided an unobstructed path for the flame kernel. Champion actually marketed plugs designed like this back when.
There is very little if any gains to be made doing either of these with todays head designs.
And your plug is fouled from being too rich, based on the picture, ie. flat dry black, I don't see shiny wet black.
Last edited by glenB; May 1, 2011 at 07:29 PM.
Safety Car
Joined: Aug 2005
Posts: 4,279
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From: North Strand, NMB, SC; Retired x 2 (US Army: 70-90 AD) (US Army: 91-16 DAC); yea, I'm old.
The OP's plug looked fouled. This is what the plugs looked like when I removed them at 99,500 miles compared to the new one:
Plug order is from right to left is front of engine to back of engine.
Passenger side:
Driver side:
Plug order is from right to left is front of engine to back of engine.
Passenger side:
Driver side: